Method updateData

app/src/UI/Widgets/Waterfall.cpp:652–744

* @brief Pulls the latest time-domain samples, runs FFT, pushes a new row. */

 * @brief Pulls the latest time-domain samples, runs FFT, pushes a new row.
 */
void Widgets::Waterfall::updateData()
{
  if (!isEnabled() || !isVisible())
    return;

  if (!UI::Dashboard::instance().waterfallRunning(m_index))
    return;

  if (!VALIDATE_WIDGET(SerialStudio::DashboardWaterfall, m_index))
    return;

  const auto& data  = UI::Dashboard::instance().waterfallData(m_index);
  const int newSize = static_cast<int>(data.size());
  if (newSize <= 0)
    return;

  if (newSize != m_size) {
    allocateFftPlan(newSize);
    rebuildHistoryImage();
    Q_EMIT historySizeChanged();
  }

  if (!m_plan)
    return;

  const double* in       = data.raw();
  std::size_t idx        = data.frontIndex();
  const std::size_t mask = data.storageMask();
  const double offset    = m_scaleIsValid ? -m_center : 0.0;
  const double scale     = m_scaleIsValid ? (1.0 / m_halfRange) : 1.0;

  for (int i = 0; i < m_size; ++i) {
    const double raw = in[idx];
    const float v    = std::isfinite(raw) ? static_cast<float>((raw + offset) * scale) : 0.0f;
    m_samples[i].r   = v * m_window[i];
    m_samples[i].i   = 0.0f;
    idx              = (idx + 1) & mask;
  }

  kiss_fft(m_plan, m_samples.data(), m_fftOutput.data());

  const int spectrumSize = m_size / 2;
  const float normFactor = static_cast<float>(m_size) * static_cast<float>(m_size);
  const float invNorm    = 1.0f / normFactor;
  for (int i = 0; i < spectrumSize; ++i) {
    const float re    = m_fftOutput[i].r;
    const float im    = m_fftOutput[i].i;
    const float power = std::max((re * re + im * im) * invNorm, kEpsSquared);
    m_dbCache[i]      = std::max(10.0f * std::log10(power), kFloorDb);
  }

  if (m_smoothed.size() < static_cast<size_t>(spectrumSize))
    m_smoothed.resize(spectrumSize);

  static constexpr float kInvSmoothingTaps[] = {
    0.0f,
    1.0f / 1.0f,
    1.0f / 2.0f,